Many methods are known in the art for combining fluid materials. Typically, the materials are combined upstream of a mix tank. Such materials are then jointly added to the mix tank and stirred until a homogenous blend is achieved. Further processing steps downstream of the confluence region may include the addition of more material(s), the addition or removal of energy, such as thermal energy, etc.
Additionally or alternatively, such materials can be mixed in a dynamic mix tank using mechanical agitation and/or alternative forms of agitation, such as ultrasonic vibration. The combined materials, or blend, may then be transported downstream and become an intermediate for further processing. Alternatively, these materials may be added to a container for ultimate sale or use.
The prior art methods and systems have several disadvantages. If such a mix tank is used, it can require considerable energy to achieve the desired mixing. If one desires to change the formulation, or even the minor materials, this change usually entails cleaning the entire tank and associated system. Cleaning the entire system can be time-consuming and laborious. Then new materials are added and the process begins again. Considerable waste of time and materials can occur.
Transients from no production or low rate production to full production rates are inevitable when changes between different products occur, etc. It is generally desirable that such a transient be over and steady state operation resume as quickly as possible. This is because one typically desires reaching steady state production rates as soon as reasonably practicable. Furthermore, product manufactured out of specification during transients may be wasted. If one were to accept a slower transient, then it is likely greater accuracy in the products manufactured during the transient can occur and less product may be wasted by having a slower transient. Thus a tradeoff is present in the art.
Often, the speed in which a system can respond to transients is limited by the hardware. For example, a flow meter which is intended to provide actual flow rate at a particular point in time may not follow and/or indicate a change in flow rate as quickly as one would like for the rate of change of the transient. For example, valves which provide flow control and ultimately the rate of material addition may not respond as quickly as one would desire. Furthermore, different sizes of valves, different operators used in conjunction with the valves, and even valves from different manufacturers may respond at different rates once a command signal is received. Yet further, the same valve may respond at different rates over different portions of the open/close cycle.
Accordingly, what is needed is an apparatus, and process of using such apparatus, which allows for quickly changing the formulation of a blend, accurately follows transients, minimizes wasted materials, and rapidly provides for homogeneity in the blend. Unless otherwise stated, all times expressed herein are in seconds, proportions and percentages herein are based on volume. Optionally, the invention may use proportions and percentages based on mass.